<p>The test is in 2 days, and I'm kind of still uneasy on these sums. As far as I know, if the question has a chart of the x and f(x) values, and the subintervals are uneven, then you just kind of make rectangles/trapezoids and add them together. But if there is no chart, then the subintervals are all even? And how exactly does midpoint summations work out? Thanks in advance!</p>